This paper investigates the no-load iron loss, on-load loss, and thermal performance of a high-speed surface-mounted permanent-magnet synchronous machine with an amorphous metal stator core (AMSC) and a titanium alloy retaining sleeve by numerical methods. The electromagnetic properties of the AMSC are tested by an experimental platform. The distributions of no-load iron loss, rated-load loss, and the thermal behavior of the motor are investigated under converter supply conditions. Finally, the loss and thermal performances of the prototype are tested and compared with the corresponding simulation results to verify the accuracy of the calculation results and the superiority of the prototype.

The small size of high-speed permanent magnet synchronous machines (PMSMs) makes the increase of loss density and the difficulty of heat dissipation. PMSMs are sensitive to temperature, especially the permanent magnet (PM), which is likely to suffer irreversible demagnetization due to the excessively high temperature. This paper investigates the loss and thermal analysis of high-speed PMSMs with amorphous alloy stator core and interior permanent magnet (IPM) rotor. First, the trajectory of magnetic flux density in typical parts of high-speed PMSM with sinusoidal and pulsewidth modulation (PWM) inverter power supply is analyzed. The core loss characteristics based on the proposed field-circuit coupled method is obtained. Then, an electromagnetic-thermal iteration calculation method is proposed to analyze the temperature distribution. The effect of different parameters on thermal behavior is investigated, which provide references for the suppression of temperature rise. Finally, the theoretical analysis is verified through the experiments based on a high-speed PMSM prototype.

A wireless switch designated for battery-supplied implantable medical devices is designed and verified based on a passive RF receiver. The switch employs wireless energy recovery and wireless identification, and consumes zero standby power. Unlike the commonly used dry reed switch, the proposed switch features high tolerance to noise and disturbance, as well as compatibility with integrated circuits. The proposed wireless switch circuit has been implemented using 0.18 µm CMOS technology, and verified in a wireless capsule endoscope prototype system.